One thing can can change a lot. On a similar level, essendon's clash, which is fair to say a popular design, is simply a red version of the grey piece of shit. Probably is a bit more visually different, but technically speaking a minor change.Other than the side panel from hell... is it really that different?
I think also a lot of people are just thinking 'why make it different at all'. It comes off very un-PC, and simply from a branding perspective, wouldn't you rather (especially Collingwood) have the same design across all teams.